1305561 has 4 divisors (see below), whose sum is σ = 1740752. Its totient is φ = 870372.

The previous prime is 1305559. The next prime is 1305571. The reversal of 1305561 is 1655031.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 1305561 - 2¹ = 1305559 is a prime.

It is a D-number.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1305511) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 217591 + ... + 217596.

It is an arithmetic number, because the mean of its divisors is an integer number (435188).

2^1305561 is an apocalyptic number.

It is an amenable number.

1305561 is a deficient number, since it is larger than the sum of its proper divisors (435191).

1305561 is an equidigital number, since it uses as much as digits as its factorization.

1305561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 435190.

The product of its (nonzero) digits is 450, while the sum is 21.

The square root of 1305561 is about 1142.6114825259. The cubic root of 1305561 is about 109.2946883631.

The spelling of 1305561 in words is "one million, three hundred five thousand, five hundred sixty-one".